This invention relates to a blind rivet, such as, for example, a blind rivet that is fastened to a member being fastened, with which the rivet body is inserted into an attachment hole in the member being fastened, such as a wall or the like, forming a closed space, and the end of a sleeve of the rivet body is deformed outwardly in the radial direction thereof, whereupon the member being fastened is clamped between that deformed sleeve portion and a flange of the rivet body.
Blind rivets, each of which comprises a hollow rivet body comprising a sleeve and a flange at one end of that sleeve, and a mandrel that is longer than the rivet body passing through the rivet body so that a grip portion extends out from the flange, are well known. An advantage thereof is the ability to fasten one member being fastened (such as a panel, for example) and another member being fastened (such as a member being attached, for example), from only one side. The mandrel has an outer diameter that allows passage through the rivet body, is formed in a rod shape, longer than the rivet body, and is provided with a grip portion and a head at the opposite end. The mandrel is assembled together with the rivet body such that the mandrel head is disposed adjacent to the end of the sleeve opposite the flange and such that the grip portion thereof extends out from the flange. In the portion of the mandrel that is accommodated inside the sleeve of the rivet body at a position separated from the head, a breakable portion of small diameter is formed, the mandrel being formed so that, when its grip portion is forcefully pulled out from the flange until the breakable portion breaks, its head widens the other end of the sleeve and its adjacent portion, outwardly in the radial direction, whereupon the member(s) being fastened is/are clamped between that deformed sleeve portion and the flange, and the blind rivet is fastened to the member(s) being fastened.
After the fastening operation, the portion of the mandrel on the grip end that is breakable and has broken is pulled in by a fastening tool and recovered in the fastening tool, but the other portion of the mandrel, that is, the portion of the mandrel including the head, extending to the breakable portion, remains in the rivet body. Therefore, there is a danger that this remaining mandrel portion will fall out of the rivet body. In cases where the blind rivet is fastened to a member being fastened that has a closed space, when the remaining mandrel portion falls out of the rivet body, that remaining mandrel portion rolls around inside that space, producing noise and even damaging the inner wall surface, which is undesirable.